Biooxidation Effluent Treatment for Acid-Consuming Gold Ores
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Solution Overview
Problem
Gold-bearing sulfide ores with significant acid-consuming minerals pose challenges in biooxidation pretreatment due to acid neutralization, making it costly and inefficient for ores with lower gold grades, as existing methods require pre-acidification or removal of acid-consuming components.
Innovation Solution
Utilizing excess biooxidation liquor effluent from a more amenable gold-containing sulfidic mineral material to treat another material with acid-consuming components, where acid neutralization and metal precipitation occur, allowing for gold release and recovery through oxidation and leaching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pre-acidification is performed to maintain acidic conditions for biooxidation, then microbial growth and gold recovery are improved, but processing costs increase significantly
Solution Approach 1:
The patent applies self-service by using the biooxidation process itself to generate the acidic conditions needed. The sulfuric acid produced during biooxidation of sulfide minerals automatically maintains the acidic environment required for microbial growth, eliminating the need for external pre-acidification and reducing processing costs while maintaining gold recovery effectiveness
2Productivity
If acid-consuming components are removed prior to biooxidation, then acidic conditions are maintained for microbial growth, but flotation costs increase
Solution Approach 1:
The patent converts the harmful effect of acid-consuming components into a beneficial function by using them as natural neutralizing agents. The carbonate minerals that would normally consume acid are instead used to neutralize excess sulfuric acid produced during biooxidation, converting a potential problem into a solution for acid management and reducing the need for costly flotation operations
3Productivity
If excess sulfuric acid is produced during biooxidation, then acidic conditions are maintained for microbial growth, but water treatment requirements increase
Solution Approach 1:
The patent converts the harmful excess sulfuric acid into a useful reagent for treating other mineral materials. The acidic biooxidation effluent is applied to refractory gold-bearing ores containing acid-consuming minerals, where the acid serves to decompose sulfide minerals and release gold, thereby utilizing the harmful acid as a beneficial processing agent and reducing water treatment requirements
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces water treatment needs, enhances gold recovery from previously refractory ores by oxidizing sulfide minerals and releasing gold, even in the presence of acid-consuming minerals, and allows for the reuse or further treatment of effluent water.
Implementation Method 1
acid in the biooxidation liquor effluent is neutralized through reaction with acid-consuming components of the second mineral material, resulting in an increase in solution pH
Implementation Method 2
there is also a significant oxidation and associated decomposition of sulfide minerals, resulting in release of gold from the second mineral material
Implementation Method 3
The acid neutralization and metal precipitation beneficially reduce water treatment that would otherwise be required
Data Source
AI summary
In one aspect the present invention provides a method of recovering gold from each of at least two different refractory gold-bearing sulfidic mineral materials. A first mineral material is subjected to biooxidation pretreatment to release gold locked within sulfide minerals. The biooxidation produces an acidic biooxidation liquor effluent that contains significant dissolved iron in the ferric form. All or a portion of the biooxidation liquor effluent is used as an acidic treatment liquid to treat the second mineral material, which contains acid-consuming minerals. During the treatment, acid-consuming minerals react with the acidic solution, raising solution pH and resulting in reduced solubility and precipitation of dissolved iron and other metals. Also during the treating, sulfides in the second mineral material or oxidized, thereby releasing gold for subsequent recovery.